1. Field of the Invention
This invention relates to the field of article supports, and in particular to a gem setting having at least one support leg of V-shaped cross-section, particularly adapted for bearing against points of marquis or pear shaped gem stones.
2. Prior Art
Gem settings normally comprise a number of metal prongs or legs radiating from a base, ends of the prongs to be bent over and hold captive a stone, without unduly concealing the stone's surface. A conventional method for forming settings for jewels and the like involves stamping out a plurality of interfittable prong members from sheet metal. Each stamped unit has two spaced prongs and the units are assembled by means of complementary notches and then soldered. The setting as so formed can be assembled into jewelry as required, for example attached to the shank of a ring, typically by soldering the attached prong members to a complementary gap in a ring shank. Settings formed from these assembled prong-pair units are typically provided to jewelers who notch the prong members adjacent their distal ends, force a faceted gemstome or the like into the notches and bend the ends of the prongs over the jewel to hold it in place in the setting.
Prong-pair members to be assembled and soldered are typically stamped from metal sheet, and when stamped have a substantially-rectangular or square cross-section along their legs. The prong-pair members each roughly form a U-shape in elevation view, being nestable and attachable to one another at the base of the U. Such systems are quite effective and popular for stones which are cut to round or radially symmetrical polygonal shapes. For heart, triangle, pear-shaped and particularly marquis stones, however, the usual prong system has drawbacks. In connection with an elongated shape such as a marquis, the prongs placed along the less-curving sides (i.e., the longer sides of the stone) may exert sufficient inward pressure against the stone, but due to obvious leverage problems, do not exert a great deal of force along the major axis of the pear or marguis-shaped stone (i.e., restricting movements of the stone end to end).
If one attempts to apply the usual type of paired-prong setting to a marquis stone, of the type having prong members of rectangular cross section, a pair of prongs must be placed at or near the pointed ends to restrict relative movement on the major axis. This detracts from the printed-end appearance of the stone. The structure also requires a relatively long prong for the ends such that it is difficult to provide the required strength of the setting that will keep the stone from loosening or being lost. According to U.S. Pat. No. Des. 195,690, a cast setting can be provided in which a portion of thinner metal encloses around the pointed ends of the marquis stone, and the setting has a pointed-end appearance. Recently, it has been attempted to form a similar structure by providing V-shaped thin sheet extensions for stubs of a short stamped prong-pair member, these thin sheet V's being aligned to enclose the pointed ends of the marquis stone and soldered to the stubs.
Soldered-on V-shaped additions to a prong-type setting are difficult to produce and have been found to lack the necessary strength. It is difficult to hold the V-shaped members in position when soldering the thin sheets to the stubs and when soldering the engaged prongs to one another. Accordingly, the cost and complexity of manufacture of settings of this type have been high, and the result is not always acceptable.
According to the present invention, a setting is provided in which V-shaped extensions adapted to enclose the ends of a marquis stone are provided in a certain type of prong formed from a continuous piece of sheet metal entirely forming at least one prong. Intermediate opposite ends forming V-shaped receptacles for the pointed ends of a marquis type stone or the like, the setting has a strong central portion of folded-over metal that is similar in size and strength to the engageable portion of a die struck prong. By folding tightly only the central portion of the sheet material, notching the center to receive one or more die struck prong members and bending the support member to bring the V-shaped ends into position to oppose one another, the thin sheet metal formed prong is substantially stronger than soldered settings, more easily manufactured, and quite effective for mounting and protecting stones. The invention is equally applicable to pear-shaped, heart, triangle and marquis stones by varying the number of V-shaped ends, the shape of the channel formed in the thin sheet and the number of supporting stamped prong-pair members used in addition to the sheet metal support member.